Put version numbers inside of individual files

Description

Why isn't there a version number inside of individual UI files? The
only number I could find was inside of the ui.core.js and jquery.ui.all.js. This was from downloading the Development Bundle.

If all files are considered to be the same number as the core, then it still helps to add it to the individual files in case just the core is updated for whatever reason and not the others and there is a mismatch.

This should be implemented with a keyword substitution (not hard-coded), just as it is for ui.core.js.

Component is listed as ui.core but is meant for all files (no option for that).